A. Field of the Invention
The present invention relates generally to a sensor assembly for automatic sinks, and, more particularly, to a sensor assembly having a flexibly mounted sensing means and an adjustable mounting means. Such a sensor assembly may be used with any type of automatic sink or in other applications requiring an automatically controlled supply of water, chemical, etc. Preferably, however, such a sensor assembly is used with surgical scrub sinks.
B. Description of the Related Art
Automatic sinks are used in order to permit a person to wash his or her hands without the need to turn on or off water supply faucets. Without such automatic sinks, a water supply may be left running or conversely require human skin contact for operation. The latter is a particular problem in surgical sinks where it is essential that the surgeon not touch any object which might be unsterile. Public restrooms are also another location where dangerous bacterial and fungal deposits on water supply faucets pose a potential health risk. This has lead to various approaches for controlling the on and off operation of faucets, particularly in surgical scrub sinks, which do not require the user to physically touch any control knob for manipulating the faucet.
Among the approaches that have been attempted is the utilization of an infrared sensor above or in the sink itself for detecting the user's hands in the vicinity of the faucet such as disclosed in Rosa, U.S. Pat. No. 4,942,631. A disadvantage with this approach, however, is that the faucet turns off when the user's hands are moved away from the immediate vicinity of the faucet, although the washing operation has not been completed. It is then necessary to turn the faucet on again when the presence of the user's hands is detected. This results in an intermittent on-and-off action of the faucet.
Attempts to avoid the above problems have resulted in variations such as changing the spread or focal length of the sensor so to detect the user's hands when they are not in the immediate vicinity of the faucet. A disadvantage with this approach, however, is the detection of other objects in the sensor beam causing false signals which result in the faucet being turned on even though the user is not present.
Another approach is illustrated in Paterson et al., U.S. Pat. No. 5,412,816, assigned to the assignee of the present invention, where a short focus sensor is fixedly mounted to the drain pipe of a sink tub and a wall at the height of the user's legs for detecting the presence or absence of the user in the vicinity of the tub. The sensor is operatively connected to a water supply on/off mechanism so as to turn on the faucet when the presence of the user is detected and to turn off the faucet when the user is absent. Such an arrangement has solved the disadvantages of the various approaches noted above. However, the arrangement does not permit the sensor to be custom fit to a variety of sinks or to be adjustably positioned due to its fixed mounting configuration.